The present invention relates to a roll-forming machine having adjustable compression between forming rolls of the forming roll stations.
Roll-forming machines typically include a plurality of roll-forming stations that are used to transform a planar sheet of metal into a component having either a C-shaped or Z-shaped cross-sectional area, for example. The component, such as a C-purlin or Z-purlin, typically has a center portion, a pair of leg portions joined to the center portion by a substantially right angle bend formed by the roll-forming machine, and a flange joined to each leg portion by a respective bend formed by the machine.
Typically, the flanges of a C- or Z-shaped component are made first by a plurality, such as three, roll-forming stations. The first of these stations makes an initial pair of bends at the desired transverse locations on the sheet, and then the successive stations for forming the flanges increase the previously made bends until the flanges are at the proper angle relative to the center portion of the sheet. The legs of the component are then formed by a plurality of roll-forming stations in a similar manner.
Each of the roll-forming stations typically includes a pair of frame members in which a pair of rotatable arbors are journalled, one arbor disposed directly above the other, and a pair of sleeves which cover a portion of the arbors, the sleeves being slidable over the arbors. Each roll-forming station includes at least two pairs forming rolls, two of the forming rolls being fixed to the arbors and the other two forming rolls being fixed to the sleeves. The circumferential ends of the upper and lower forming rolls are vertically spaced apart by a distance corresponding to the thickness of the sheet of material being bent, and the shape or contour of the forming rolls controls the degree to which the sheet is bent. The use of sleeves which are slidable on the arbors and which rotate with the arbors allows the horizontal spacing of the forming rolls on each arbor and sleeve to be varied so that the transverse widths of the center portion and the leg portions of the components being formed can be adjusted.
The sheet of material is forced through the roll-forming machine by friction between the sheet and the rotating forming rolls. The forming rolls of a plurality of the roll-forming stations, e.g. the forming rolls of every other station, are rotatably driven to ensure that there is enough driving power to force the sheet through the machine.
In the case of a C-shaped component, the flanges are made by bending the transverse ends of the sheet in the same direction, for example, downwards, whereas for a Z-shaped component the flanges are made by bending the transverse sheet ends in opposite directions. After the flanges are formed on the transverse ends of the sheet, the legs are formed by a plurality of roll-forming stations by a similar process. To form a component in the above manner, up to ten or more roll-forming stations may be incorporated in the roll-forming machine.